Antibiotics are the primary treatment for Lyme disease; the most appropriate antibiotic treatment depends upon the patient and the stage of the disease. The antibiotics of choice are doxycycline (in adults), amoxicillin (in children), erythromycin (for pregnant women) and ceftriaxone. Alternative choices are cefuroxime and cefotaxime. Macrolide antibiotics (such as erythromycin) have relatively low efficacy when used alone; they are administered to pregnant women since they are harmless to the fetus, in contrast with most Lyme-disease antibiotics.
Results of a recent double blind, randomized, placebo-controlled multicenter clinical study, done in Finland, indicated that oral adjunct antibiotics were not justified in the treatment of patients with disseminated Lyme borreliosis who initially received intravenous antibiotics for three weeks. The researchers noted the clinical outcome of said patients should not be evaluated at the completion of intravenous antibiotic treatment but rather 6–12 months afterwards. In patients with chronic post-treatment symptoms, persistent positive levels of antibodies did not seem to provide any useful information for further care of the patient.
In later stages, the bacteria disseminate throughout the body and may cross the blood-brain barrier, making the infection more difficult to treat. Late diagnosed Lyme is treated with oral or IV antibiotics, frequently ceftriaxone for a minimum of four weeks. Minocycline is also indicated for neuroborreliosis for its ability to cross the blood-brain barrier.